Shielded cable connectors



Sept. 4, 1956 R. J. MELCHER SHIELDED CABLE CONNECTORS 2 Shees-Sheet 1www.

Filed Feb. l1, 1955 INVENTOR /Pobef/ d Me/c/zef" y BYz HTTlV-) Sept. 4,1956 R. J. MELCHER SHIELDED CABLE CONNECTORS 2 she'ets-sneet 2 FiledFeb. ll, 1953 VIII'II."

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United States Patent O SHIELDED CABLE CONNECTORS Robert 'J. Melchor,Toledo, Ohio, Aassignor to Erich 1.

Tilen'ius, Gerald L. RandolphGeorge A. Goss, and Tohu F. Iiones, Jr.,Toledo, Ofhio, and John Jones, Sr., Plattsburg, N. Y., a copartnershpdoing business ras fH. 1H. Buggie and Company, Toledo, hio

' Application February 11, 1953, 'Serial No. 336,289

'3 SClaims. (Cl. 339-143.)

This invention relates to cable .connectors for .rapidly connectingshielded zelectrical cables .to .cased units of vradar and `otherelectronic equipment, .particularly ,such .equipment as is connected .byIpulse carrying cables.

fIn vmany .military and kother -electronic installations it is desirablethat units be separately .enclosed in k.protecf tive .and insulating orshielding -casings not .only to protect the operation ofthe .equipmentelectrically but .to prevent ingress of moisture vand dirt andtofacilitate Ithe vportability of the installation by breaking it up.into vsmaller units. Where such units are to -be .connected .by cablescapable Aof :handling yeryihigh voltage impulses, intricate electricalcircuits are involved Aand the connecting cables .must ,be not .onlyphysically tough yand capable of handling the .electrical loads buttheyshould be .provided fwith yconnectors which effectuate ,theelectrical .and Iphysical .connection rapidly Y.and simply.

ltis, 'thereore, Vthe principal object of this invention :to provide .aeonnector set designed to facilitate rapid .assembly, vcompleteprotection against moisture and dirt, .and electrical fshieldingandinsulation.

A :connector-set embodying the invention is illustrated in the attacheddrawings .in .a form particularly designed for use in a double.shielding system sometimes ...called la .tri-axia1 .system :and theconnectors .in their `several :elements :are `Adesigned to -make .orbreak ,as Vmany .as th-ree .or 'rmoresimultaneous circuits with twoconcentric shielding systems :associated with Ya .central conductor.

The purposes :and :construction .of 4a ycable connector Iembodying .theinvention .will be more clearly understood from the specification and.from the y.dra-wings, .in which: Fig. l is a vertical sectional view,with some ,parts 'broken away, of a connector plug and .receptacleembodying :the invention, the plug and vreceptacle beingfshownin :their:disconnected positions.

fFig. 2 is a view similar to Figfl lbutfshowiug [the plu and receptaclein assembled position.

Pig. is .a `view 'similar to Fig. .1 but showing Va second plug andmodified receptacle in disconnected position.

Fi1g.4 is a fragmentary viewin vvertical section showing vhow the plugand :receptacle ofFig. .3 make their connections.

Fig. `5 is a lgreatly enlarged `view in :perspective l.of -a conductorvconnector pin .of a type employedl inthe .plugs and :receptaclesembodying the invention.

Fig. 6 is .a'further :enlarged verticalfsectional view .on the line6--61of.Fig. 5.

`Fig. 7 is .a simplified hookup idiagramfillustratiug how the receptacleVand plug of Fig. :l are associated with the similar plug andmodiiiedreceptacle .of,.Fig. .3 fto'establish a double .shielded:system..-b.etw.een two equipment units.

Pulse cables of .the general type :illustrated in zthe'drawings `and,for which connector sets '.comprisingra connector plug embodying. theinvention .and generally indicated :at 9 in Fig. `1 are designated, :are4'of .several general ttypes. Among these .types lis .a tri-axial cablewhich mayrcornprise ta centralzconductor' 10 (Fig. .-1) lvthat islsurrounded by a layer of electrical insulation 11 which, in turn, 1s

Z enclosed in .a braided wire shield 12. Exteriorl'y of the shieldlZ.there .are aseeond insulating layer 13, an outer braided .wire shield14 .and ,a tough exterior jacket l5.

In the cable illustrated in the drawings the insulating layers ,lland 13.are .shown as uniform in characteristics, but some rpulse cables havecorresponding layers which are double, i. e., which have .a .thin layerof conducting rubber, for example, immediately circumjacent theconduetor .10 and `a layer `of insulating rubber .around the Aconductingrubber and inside the metal shield 12. While 'such .a .conductor Yis notillustrated in the drawings, as -will appear later in Vthe description,the .connector sets embodying .the invention are ladapted to be usedeither with .the type of conductor specically illustrated or with .aconductor .such .as that just described.

The cable as a Whole is generally indicated with th :reference number 16lin Pig. l and the other gures Aand is, as a whole, reasonably Aliexiblekto allow it to be coiled --and to be used .to connect -electronic unitsor pieces of equipment which .do not lie in lixed or .aligned positions.ACables .of .this general Atype, of course, are well-known in the .artand their need for flexibility explains why the shielding .layers 12 and14 are `fabricated from an open =woven wire braid, for example, so that.the cables possess za high degree :of '.tlexibility.

In preparing the end of a tri-axial :cable Ysuch as the cable -16 iofthe .drawings for attachment to va connector plug embodying theinvention, .the several ,concentric layers' are .eut :at staggeredpoints along the cable 16 .-near :its iend. Each Aof .the layers nearerthe center extends .further toward -the end, ie., more 'ofithe jacket 15is cut .away than of the metal shield 1.4 and, similarly, eachsuccessive layer .extends an appropriate further distance toward the endof :the conductor.

Referring now specifically to Fig. l, at the very end of @a .cable beingprepared for assembly a ,short length of .center metal'conductor vlllislaid bare forming a project eingrprong .17 which is inserted in .asocket at :the rear of, .and .soldered to, aconneetor pin 18. .In Fig.l, the .Con- .nector pin '1:8 is 'shown as .a male connector pin, i. e.,-having a single point.

ilu .preparing fthe cable 16 Y,to provide the extending pron-g "17 onthe .conductor 10, .its insulating vlayer 11 .is ycut .backladistanceysuch that when'the .cable "is thrust into .anaxialopening 19 in aspool-Llikeinsulator 20., .ashou'lder 211cm on the end of thefcenterinsulation 11 .abuts the end .of a sleeve 22 inserted in the forward endofthe opening 19 of the insulator 2l). The sleeve 22 is ,of such length.relative to the length of the :prong 117 :and .connector pin 18th-ataconsiderable length tot the connector pin 1S-pro- :trudes :beyond the.end of the insulator 20. The sleeve y22. may be-.moldedtrom.conductingrubber when the connector .set v'is used with a cable having a layer oflcon- .ducting rubber adjacent the ,central conductor .10. .Both

Ithe insulator 2t) .and .sleeve 22 .areexible The insulator 20 islocated interiorly of a generally .tubular :shell 23 being held thereinby the .engagementof a :split expansion ring 24 in an undercut annularlgroove .z251in'the wall of the shell `23, the ring V24 y.also engagingiin :an annular collar 26 which is molded in the body of lthe insulator20. The vinsulator 20 has a disk-like head ..27 `formed on fits forwardend vwhich engages tightly against the .end ofthe shell 23 when theinsulator 2.0 has been inserted suiiciently farinto the shell 23 for-thesplit ring 24 to-expand into'the groove 25.

lexplained with respect to .assembly of a ,connector 'plug land xa:connector .receptacle embodying theinvention, en-

gagement of the ends of the insulator 20 and sleeve 22 lv2,762,025 vwith parts of the connector receptacles results in attening theinsulator 2d and sleeve 22 axially, wiping air radially outwardlybetween their surfaces and the engaged surface in the receptacle.

The rear end of the shell 23 has a pair of outwardly radially extendingflanges 28 and 29 which are axially spaced a distance sufficient toaccept a conventional O- ring 30.

The shell 23 is fixedly positioned in and insulated from a tubular outershell 31 by means of a pair of insulating sleeves 32 and 33. The sleeve32 is positioned circumjacent the body of the shell 23 in front of theange 28 and bears against a front lip 34 formed on the outer shell 31.The other insulating sleeve 33 bears against the rear edge of the llange29, which also is the rear end of the inner shell 23 and the entireassemblage of the three units of sleeve 32, shell 23, including theinsulator 20, and sleeve 33 is permanently associated by spinning over alip 35 formed at the rear of the tube-like body of the outer shell 31.

It will be observed that the inner diameter of the lip 34 of the shell31 is greater than and thus spaced from the outer wall of the innershell 23 so there is no Contact, either physical or electrical,therebetween.

The outer shell 31 has an outwardly directed ange 36 near its frontedge. A plurality of spring fingers 37 formed either independently orfrom a comb shaped strip of resilient conducting metal are soldered orotherwise rmly secured to the flange 36. The fingers 37 extend generallyforwardly laround the exterior of the shell 31 being flared outwardlyand then sharply returning with ends that are received in an annulargroove 38 but in the exterior of the outer shell 31 near its front end.The annular groove 38 accommodates the bent inward ends of the fingers37 when the fingers 37 are squeezed inwardly as by being forced into acylindrical cup, for example, having an internal diameter less than theeffective exterior diameter of the mass of lingers 37 in their outwardlyflared position.

The outer shell 31 is provided with a coupling 39 which is generally cupshaped and surrounds a portion of the forward part of the shell 31,having an inwardly turned rear edge 40 between which and the rear sideof the flange 36 on the exterior of the shell 31 there may be locatedeither a simple coil spring 41 or a plurality of, for example, bentwashers serving the same function. The front inner edge of the coupling39 is interiorly threaded for assembly with a receptacle as will laterbe described.

At the rear tubular portion of the outer shell 31 which surrounds thesleeve 33, and immediately forwardly of the inwardly spun lip 35, theexterior of the body of the outer shell 31 is threaded.

The rear end of the bore of the inner shell 23 has a chamfered corner 42for engagement with the beveled front end of a ferruleV 43. The ferrule43 loosely lits over the exterior of the layer of insulation 11 and hasa thin tubular body which is adapted to slide between the surface of thelayer of insulation 11 and the inner shield 12. When the ferrule 43 isthrust into the position illustrated in Fig. l, it flares the shield 12outwardly and also flares outwardly the end of the outer insulatinglayer 13. As can be seen in Fig. l, the insulating layer 13 is cut awaya little farther than the shield 12 leaving a short portion of theshield 12 extending beyond the insulation layer 13 on the exterior ofthe ferrule 43 so that it can be soldered thereto. When the cable isprepared for connection to the connector plug embodying the invention,the shield 12 and outer insulating layer 13 are both cut; back distanceschosen so that when the ferrule 43 is mounted thereon and soldered inplace, its axial distance: from the shoulder 21 of the inner insulation11 aligns the ferrule 43 for positioning against the chamfered corner 42of the inner shell 23.

The exterior of the end of the outer insulation mass 13 is surrounded bya tubular insulating sleeve 44 which fits snugly within the interior ofthe sleeve 33 and extends between the rear edge of a flange 45 on theferrule 43 and the front edge of a at flange 46 on -a second ferrule 47.The ferrule 47 ts relatively snugly over the exterior of the outermostlayer of insulation 13 similarly having its thin tubular body thrustbetween the exterior of the layer of insulation 13 and the outer shield14. As is the case with the inner elements of the cable, the shield 14and the outer jacket 15 are cut away at such distances from the end ofthe conductor 11 that upon assembly of the device, the ferrule 47 bearsagainst the rear edge of the insulating sleeve 44.

The ferrule 47, sleeve 44 and ferrule 43 are all thrust tightlyforwardly by the clamping action of a rear body member 48. The member 4Sis generally cup shaped having a forward tubular wall 49 that isinternally threaded to match the threads on the exterior outer shell 31.A flat washer-like sealing gasket 50 is positioned between an annularshoulder 51 on the member 48 and the turned over lip 35 of the outershell 31.

Just rearwardly of the shoulder 51 of the member 4S a second step-downshoulder 52 engages the rear edge 53 of the flat flange 46 of theferrule 47. Thus when the body member 48 is assembled on the rear of theouter shell 31 by engaging their respective threads, the sealing gasket50 is tightly clamped between the shoulder 51 and the lip 35 of theouter shell 31 and the shoulder 52 engages the ferrulc 47 to hold thesleeve 44 and ferrule 43 tightly in their respective positions.

The rear end of the member 48 is reduced in diameter and forms a throat54 extending rearwardly from an inwardly directed lip 55. The lip 55 hasan inner diameter such that it ts around the exterior of the cablejacket 15. The interior diameter of the throat 54 is, however,substantially larger than the exterior diameter of the jacket 15 and abeveled edge locking collar 56 is insertable therebetween. The rear edgeof the lip 55 is beveled with a reverse bevel so that its inner edgeextends rearwardly along the outside of the jacket 15 toward the lockingcollar 56 farther than does its outer edge. The beveled edge of thecollar 55 is correspondingly shaped and its rear edge is oppositelyshaped to match the cone shaped end of an axially movable thrust collar57 which is held in place and may be thrust forwardly by a threaded cup58, the cup 58 being threaded on the exterior of the throat 54 andhaving an inwardly directed lip 59 which bears on the rear edge of thethrust collar 57. When the cup 58 is threaded onto the exterior of thethroat 54, the thrust collar 57 is slid forwardly causing the collar 56to bulge inwardly and tightly grasp the exterior of the jacket 15 of thecable 16. The clamping collar 56 and its cooperating lip 55 and thrustcollar 57 are more cornpletely disclosed and claimed in Sprigg Patent2,513,115 and do not constitute a part of the instant invention, beingdisclosed herein merely as illustrative of means for securely clampingthe cable 15 in a connector plug embodying the invention.

As has been explained above, preparation of a triaxial cable 16 forassembly in a connector plug embodying the invention requires that eachof the several concentric layers be cut back certain distances. Theorder of assembly of the parts is as follows: The cup 53 is first slidrearwardly into the cable followed by the following parts in the orderrecited: The thrust collar 57 (hard material such as metal or aninflexible plastic), the clamping collar 56 (resilient material such asnatural or artificial rubber), and the body member 48. The jacket 15 andouter shield 14 are then cut back to provide an exposed portion of theshield 14 and the ferrule 47 is slid over the exterior of the insulatinglayer 13, forced into the position shown, and soldered to the end of theshield 14. The outer insulation 13 and inner shield 12 are then cut backto an appropriate length with respect to the position of the ferrule 47and the ferrule 43 is slid over the inner insulation layer 11 andsimilarly solarcades dered'to the inner shield 12. The sleeve 4'4whichmay be made of a tube of resilient insulating material or ofrelatively stil insulating .material which has been cut axially,vpreferably the latter, is then positionedk exter- 4iorly of the cutback end of the outer insulation 13 and inner shield 12 in positionbetween the two kferrules 47 and 43. As earlier explained, the end ofthe inner insulating layer 11 and the conductor k1() itself are thenprepared and soldered to the connector pin 18. The sealing gasket 5.0 isthen dropped into place in vthe bottom of the forward cup shaped portionof the member 48 against 'the shoulder S1.

With these several parts 4in Vposition on the cable '16, 'its end isthen thrust into the axial bore in the insulator 20 and the body member48 threaded onto the exteriorfof the shell 31 until the members lareclamped together with the gasket '5'0 tightly clamped between the spunover lip 35 and lthe shoulder 51. The clampingcollar 56 and rthrustcollar 57 are then slid forwardly land the cup 58 threaded onto theexterior of the throat 54 tightly enough to `cla-nip the lcable 16 inposition.

"Similarly, 'a connector plug is assembled fon the `other end of -thetri-axial cable to be used lfor `connecting the two 'electronic unitsinvolved. In Fig. 3 there is illus* trated, partly in elevation andpartly in section, :a ronnector plug generally indicated at -60 andidentical with the connector plug just described in detail and shown .inFig. l wit-h the single exception that itis equipped 'with :fa female-connector pin 61 (see also Figs. 5 and :6) in place ofthe maleconnector pin1r8 of Fig. 1. rThe female connector 'pin l61 is formedfrom a tube 62 which :is split axially forming several fingers 63 `whichare bent inwardlytoward each other and .adapted :to be spread upon theentry therebetween of a :male connector pin 118,. is .theucase with the'male connector pin 18 of the connector plug :shown in Fig. .1, thefemale connector pin 61 ofthe plug 60 yshown vin Fig. 3, is soldered tothe center conductor 10..

In tall other respects the connector plug 60 illustrated in Fig. 3 :maybe :identical 'with the connector plug shown in Fig. l and, therefore,.corresponding parts in .'Fig. 3 have been given the same numbers -asthose :same ,parts shown in Fig. .1. vAs can also be seen in Fig. 3, the-rear outer .surfaces of the member 48 and `cup 58 may ybe formed withats 64 and 65 respectively, forengagement by wrenches to facilitatetheir assembly.

.Referring again tto Fig. .l `and `more specifically .to the leftside ofFig. l, there .is shown 4in .cross 4section .faconn'ector receptacle`generally indicated by .the reference number `66 :adapted to be.assembled to =a connector plug embodying ,the invention. The receptacle.66 has a main insulator 67 which preferably is .molded from .insulatingmaterial having little, if any, resiliency, for -example `a syntheticresinous material of .high `di-electric properties.

As can be seen in Fig. l, the ,insulator 67 is .generally elongated andhas a .center bore 68 -in which a 4conductor 69 ,is trnolded. Theconductor .69, may, for example, be provided with flanges 70 at.oneormore places along its length which position it securely in theinsulator 67.

.The right or front end of the conductor 69 has a counterbore 7.2 ofsuch size -to receive, `in this instance, a 'female connector pin 71.The connector pin 71 'is retained in the counterbore "72 by sweatingsolder into annular grooves erV openings cut lin the exterior of theconnector pin 71. The .exterior of the rear portion of the insulator 67.may be molded to provide several conventional insulator anges 73 toincrease the creepage distance along the surface of the insulator '67.

At its forward end v.the insulator 67 has two step-down tenons. Thefirst tenon '74 'is of such diameter that a conventional O-ring 75 canbe positioned between the exterior of the tenon "74 and the interior ofa socket "76 in the rear of a receptacle shell '77. A second ten'on o'nthefbo'dy 67 lis of such diameter 4as Lto tit snugly in an annular lip'79 on the shell 77. A 'plurality of an inner wall 81 of the shell 77and extend vforwardly from the forward end of the insulator 67 being'bent slightly inwardly with their ends 82 bent outwardly and receivablein an undercut annular groove 33 .formed in the shell 77. The shell '77has a tubular cylindrical rim 84 which extends forwardly from thefingers 80 and is of 'larger diameter. l

The insulator 67 ,is lixed in place in the shell '77 'by being insertedfrom the rear until the forward edge of the tenon V74 strikes the rearedge of the lip "79 where.- upon a lip 85 protruding rearwardly from themain body of the shell 77 and surrounding the receptacle insulator 67 isspun downwardly .around a shoulder 86 on the insulator 67. Y

The shell 77 is assembled in place in a bore in a unit panel 87 by meansof a locking nut '88 engaged on the threaded exterior of the shell 77.The shell '77 .has a radially spaced axially extending .lip 89 which is`.tightf cned against one side of the panel S7 by the tightening of thenut 88 against the other side .of the panel 8.7. The lip 89 and ltheexterior of the shell 77 form an annular groove for an O-.ring 9i).

Fig. 2 illustrates how the plug 9 and receptacle 66 separatelyillustrated in Fig. l are assembled to each other. 'The connection ismade by axially moving the cable plug 9 to insert its male connector.pin 18 into telescoping connecting relationship with the associatedfemale connector pin 7.1. Simultaneously therewith the forward end oftheinner shell 23 strikes 4the outwardly `bent ends 82 ofthe .lingers 80and the edge of the rim S4 ofthe receptacle 66 strikes the inwardlydirected ends of the ngers 37. vThe shell 2.3 enters between the lingersflexing them outwardly and the fingers 37 enter the rim 84, 'flexinginwardly. Y

At this point the coupling 39 is slid toward 4the -re` ceptacle I66compressingthe `spring or washers fi-1 until the threads `on thecoupling 39 are engaged with the threads on lthe exterior or" thereceptacle 66. Rotating the coupling 39 then compresses the spring orwashers 41 `further and moves the connector plug 9 into the receptacle66 establishing considerable overlap vlbetween the elements making thexcthr-ee simultaneous :and separate -electrical connections. hese threesets of .elements Iare fas follows: Conductor-connector pins 218 and 71;.inner shieldfsh'ell ,23 iand fingers 181).; outer lshield-ngers 37 andrim 84. By reason of the y:contact between the clamping inut 88 and lip89 lwith the panel 87, the -shell of .the receptacle .6,6 viselectrically `connected to the panel 87. This establishes an .electricalconnection between the panel 87 and `both the outer shield 14 .and innershield 12 of -the tri-axial cable 16.

As the plug 9 seats home solidly in the -receptale:.6.6 the lend of the,sleeve 22 engages the end'of the .insulator 67 which, it will be:observed in Fig. l, is planar .and perpendicular to the vaxis .of theplug and receptacle. Upon engagement .of the spherically :shaped end `of.the .sleeve 2.2 and immediately thereafter, the spherically shaped endof the vinsulator 2t) with the planar end of the .insulater 67, the endsof the resilient insulator20 and `sleeve 22 are squeezed progressivelyoutwardly `against the .end of .the insulator 67. This displaces theresilient material from which the linsulator 20 and .sleeve 22 raremade, gradually flattening their ends and wiping any air out frombetween the two engaged surfaces. As will be bserved in Fig. 2, when the.plug 9 and receptacle 66 are completely assembled, the ends of .theinsulator 20 and sleeve 22 all lie in a single plane and tightly engagedthus preventing corona etiects. l

As was Vearlier explained, in some co-axial Aand tri.- axial jpulsecables, 'the linner `layer '-11 vof insulation .is comprised of twoconcentric layers, the Iinner of these being conducting material andIthe 'outer non-conducting material. If a cable of this type isemployed, the diameter of the conductor 69 in the receptacle 66 is suchthat it is equal to the diameter of the conducting rubber layer on theexterior of the conductor 1t). It is necessary therefore that the end ofthe conductor 69, which is coplanar with the end of the insulator 67,should come into rm contact with conducting material of the same size.In these instances the conducting rubber sleeve 22 establishes contactwith the end of the conductor 69 and, at its other end, is in contactwith the end ot the cnducting rubber layer exteriorly of the metalconductor at the rear or right end of the sleeve 22, i. e., at theshoulder 21 (Fig. 1) cut on the inner layer 11 of insulating material.In order to permit the wiping action described above, the sleeve 22which must under these conditions serve as a conductor, cannot be madeof metal but, is made of resilient conducting material as set forth.

As has already been stated, the connector plug 6G of Fig. 3 issubstantially identical with the connector plug as described in detailwith reference to Figs. l and 2 except for the type of connector pinemployed therein. In Fig. 3 the connector pin 61 is a female connectorpin and and it makes connection with a male connector pin 91 which ispositioned in a receptacle generally illustrated at 92 in Fig. 3. Thereceptacle 92, while generally similar to the receptacles of Figs. l and2, is different in one important particular. The receptacle 92, like theplugs 9 and 60, has two concentric relatively insulated shells whichtake the place of the single shell 77 of the receptacle 66. Thereceptacle 92 shown in Fig. 3 has an outer shell 93 which is providedwith an axially spaced lip 94 for compressing an O-ring 95 against apanel 96. The shell 93 has a tubular section 97 of larger diameter whichis exteriorly threaded for receiving a locking nut 93 by means of whichthe receptacle 92 is clamped in place in the panel 96.

The receptacle 92 also has a generally tubular inner shell 99 which isspaced from the outer shell 93 by a pair of annular insulating washers100 and 101. The

inner shell 99 has a pair of spaced anges 102 on the eX- terior of itsbody between which an O-ring 103 is positioned. When the inner shell 99,insulating washer 100, O-ring 103 and insulating washer 101 are allassembled in the tubular body of the outer shell 93, they are positionedby a shoulder 104 on the inside of the outer shell 93 and clamped inposition by spinning over a lip 105 at the rear of the shell 93.

The inner shell 99 is generally tubular in shape. It has a rear bore oflarger diameter which receives a molded insulator 166 that is held inplace in the shell 99 against a shoulder 107, with an O-ring 103 in anannular groove formed by the shoulder 107 and an opposed shoulder 109 onthe insulator 106. The insulator 106 is clamped into position byspinning over a lip 110 at the rear of the inner shell 99.

The male connector pin 91 is integral with or soldered in a conductor111 which is molded in the insulator 106. The front or outer end of theinsulator 106 extends into a tubular portion 112 of the inner shell 99and a plurality of spring lingers 113 are mounted in the shell 99 in amanner identical to the mounting of the iingers 80 in the shell 77 ofFig. 1. The inner shell 99 additionally is provided with a connectionscrew 114.

Assembly of the plug 6i) in the receptacle 92 is similar to assembly ofthe plug 9 in the receptacle 66 described above, i. e., the two aremoved axially relative to each other until the connectors 61 and 91engage and the fingers 113 slide over the end of the shell 23 of theplug 60 and the ngers 37 enter a rim 115`7on the end of the outer shell93. Continued axial movement of the plug 60 engages these pairs ofelements and the coupling 39 is threaded onto the threaded exterior ofthe rim 115. This establishes three contacts as follows: Connector pins61 and 91; inner shell 23 and inner shell 99; outer shell 31 and outershell 93. In this instance only the outer shell 93, however, iselectrically connected to the panel 96 and, therefore, the inner shell23 of the connector plug 6G and, consequently, the inner shield 12 ofthe cable are connected only to the inner shell 99 of the receptacle 92.

As was the case when the connector plug 9 was assembled in thereceptacle 66, the ends of the insulator 20 and sleeve 22 of theconnector plug 60 of Fig. 3 are engaged with and wiped along the planarend ot the insulator 106 of the receptacle 92.

The assembled position of parts of the connector plug and receptacle 92are illustrated in Fig. 4 where it can be observed that the ends of theinsulator 20 and sleeve 22 have been attened as described.

The screw 114 is provided on the inner shell 99 for making a connectionbetween the inner shell 99 and a pigtail conductor indicated at 116 inFigs. 3 and 7.

In Fig. 3, a broken line bearing the legend oil level indicates that thereceptacle 92 is assumed to be immersed in oil in the unit of which itis a part. Of course, the receptacle 92 may be employed in other unitswhere it is not immersed in oil but in such a case it would be providedwith conventional insulator anges like the flanges 73 in Fig. 1.

Fig. 7 diagrammatically illustrates a cable and connector assembly fortwo electronic units indicated at A and B. The unit A is the unitenclosed in the casing of which the panel 87 (Fig. 1) is a part and theunit B is a unit enclosed in the casing of which the panel 96 (Fig. 3)is a part. In Fig. 7 it is shown how the outer screen-like shield 14 iselectrically connected to the single shell 77 of the receptacle 66 andto the outer shell 93 of the receptacle 92. The shell 77 of thereceptacle 66 and the outer shell 93 of the receptacle 92 arerespectively grounded to the casings S7 and 96 which, in turn, asindicated in Fig. 7, are connected to Ground The inner shield 12 iselectrically connected to the shell 77 of the receptacle 66 and to theinner shell 99 of the receptacle 92. The inner shell 99 of thereceptacle 92 is connected through the pigtail 116 to the unit B which,in this particular arrangement illustrating the type of groundedconnections made, is insulated from its casing 96. In a circuit of thistype the central conductor 10 carries a pulse of current in thedirection of the arrows in Fig. 7.

In general, cable connectors embodying the invention are adapted for usewith any tri-axial cable of the type generally referred to when used forproviding the double shielding effect illustrated generally in Fig. 7.The circuit illustrated in Fig. 7, of course, and the electronicinstruments necessitating their employment, do not constitnte part ofthe instant invention.

Having described the pulse cable connectors embodying the invention, Iclaim:

1. A connector set for a cable having a central con-` ductor, a firstlayer of insulation surrounding said conductor, a iirst metal shieldconcentric therewith and located externally of said first layer ofinsulation, a second insulating layer external if said first shield, asecond shield external of said second insulating layer and an exteriorjacket, said connector set comprising, in combination, a connector plughaving a main body member, comprising, an elongated, generally tubularinsulator, said insulator having an axial bore adapted to receive aprotruding length of the conductor and the tirst layer of insulation,inserted therein from the rear, a tubular inner conducting shellsurrounding said connector insulator, an external connector shellsurrounding said inner shell and spaced therefrom, means insulating saidexternal shell from said inner shell; a tubular shaped rear memberremovably connected to said body member coaxially therewith, said rearmember having an axial bore adapted at the rear end to receive saidcable, in-

9 cluding all of its elements and its jacket, and two conductingferrules, the first of said ferrules having a thin tubular body portionadapted to slide axially over the rst layer of insulation and beneaththe first 0f said shields, the second of said ferrules having a similarbody adapted to slide over the exterior of the second insulating layerand beneath said second shield, each of said ferrules being electricallyconnected to the associated one of said shields, the forward portion ofeach of said ferrule bodies having a radially extending portion engaged,respectively with said inner shell and said conductor shell when saidrear member is fully assembled on said main body member; a receptaclefor said connector plug comprising a generally tubular insulator havinga central bore adapted to receive a length of central conductorengageable with the central conductor in said connector plug, an innershell surrounding said insulator, a receptacle shell surrounding andinsulated from said inner shell; and cooperating means on said connectorplug and said receptacle for establishing electrical contact betweensaid inner shells and between said connector shell and said receptacleshell for removably connecting said plug and said receptacle.

2. A connector set for a cable as defined in claim 1 in which thereceptacle shell and the inner shell of the receptacle are electricallyintegral, whereby the inner and outer shields of the cable are commonlyconnected at the receptacle.

3. A connector set for a tri-axial cable having a central conductor, arst external metal shield concentric therewith, and spaced therefrom, asecond external shield spaced from said rst shield and a layer ofelectrical insulation exterior of each of said elements, said connectorset comprising, in combination, a connector plug having an innerinsulator, said inner insulator having an axial bore adapted to receivea protruding length of the `conductor and the rst layer of insulation,an inner conducting shell surrounding said connector insulator, anexternal connector shell surrounding said inner shell and spacedtherefrom, means insulating said external shell from said inner shell; acable holding device removably connected to the rear of said bodymember; and two axially and radially extending conducting ferrules, eachof said ferrules being of size and shape to be connected to one of saidshields electrically and to contact electrically one of said shells; areceptacle for said connector plug comprising an inner insulator adaptedto receive a length of conductor engageable with the central conductorin said connector plug, an inner shell, a receptacle shell andinsulating means between said elements; and cooperating means on saidconnector plug and on said receptacle for establishing electricalcontact between said inner shells and between said connector shell andsaid receptacle shell, respectively.

References Cited in the tile of this patent UNITED STATES PATENTS2,134,946 Hurley Nov. 1, 1938 2,379,942 Webber July 10, 1945 2,449,983Devol Sept. 28, 1948 2,460,304 McGee Feb. 1, 1949

